Simulators are well known in the art having found applications in such diverse fields as aircraft pilot training and amusement rides. In general, known simulators include a motion base having one or more seats and a plurality of programmable actuators which displace the motion base from a rest position in accordance with a predetermined sequence of drive signals. Synchronized with the motion base movement is a motion picture illuminated on a projection screen directly attached to the motion base or in the immediate environment. A controller is sometimes included to provide for the synchronization between the motion base displacements and the accompanying audio-visual work. Alternatively, the audio-visual images and motion base control signals are simultaneously recorded in media if, for example, the resultant program is to be repeatedly used.
Known simulators include the amusement ride apparatus disclosed in U.S. Pat. Nos. 4,752,065 and 4,798,376 which includes a motion base that moves and tilts passengers viewing a motion picture. A plurality of passenger holding frames is provided which are all synchronously moved by separate sets of actuators. A film is shown to passengers on a stationary screen. The passenger holding frames are each pivoted up and down on a beam which is supported only by two largely vertical actuators while two pairs of links or arms limit the movement of the beam.
U.S. Pat. Nos. 3,923,300 and 3,865,430 to Tanus disclose a theater chair that comprises a support structure and a chassis having a back, arms and a seat moveably affixed to the chassis. There is a provision for movement in the vertical and horizontal directions. The Tanus chair comprises part of a overall system wherein control signal information is coded on motion picture film. The chair is operated synchronously with the playing of the motion picture to enhance the realism of the movie.
An example of a game machine is provided by U.S. Pat. No. 4,478,407 to Manabe. The '407 machine includes a motion base wherein a seat is pivotally mounted at perpendicular hinge points on a planar platform with motion in a perpendicular third dimension being accomplished by actuators configured therewith. The '407 device is designed to generate roll pitch and yaw sensations, as well as vertical movement.
A motion system for flight simulation is disclosed in U.S. Pat. No. 3,645,011 to Callanen. The '011 flight simulation system includes three spaced-apart hydraulic actuators for imparting translation to respectively associated reciprocal pistons. One of the actuators is positioned in a vertical plane containing the longitudinal or roll axis of a grounded flight trainer and the other two actuators are spaced from the roll axis at vertical positions on either side transverse to that axis.
Another amusement ride is disclosed in U.S. Pat. No. 4,066,256. The '256 amusement ride creates the illusion that the passengers are seated in a rapidly maneuvering vehicle by applying forces to the passengers in synchronism with the display of a motion picture image. The '256 apparatus includes a passenger holding frame that has three locations resting on hydraulic rams that can tilt the frame or move it up and down with a film projector and viewing screen-connected to the frame to move with it.
U.S. Pat. No. 4,846,686 discloses a motor vehicle simulator with multiple images. The '686 simulator is characterized by a conventional front looking "driver point of view" image which would be seen by a driver looking through a windshield. Another section of the images displayed with the '686 simulator includes images that were recorded by one or more cameras which were facing rearward. An individual in the simulator is simultaneously presented with a forward looking "driver point of view" image and with other images representing what would be seen by the-driver looking towards the rear of the simulator vehicle.
U.S. Pat. No. 4,276,030 discloses a pivotable vehicle simulator with one end of an upper frame carrying an occupant station of a simulated vehicle. The upper frame is mounted to a base frame which is pivotal about a vertical axis. A dummy steering wheel is provided at the occupant's station and is linked to pivot the upper frame. Combined rotary and translation bearings support the other end of the upper frame on a shaft carried on a base frame to accommodate the pivotal movement about the vertical axis and also to provide a small upward pitching of the upper frame during pivoting of the upper frame in either direction from a central position so that gravity acts to restore the upper frame and steering wheel to centered conditions.
Other known simulator systems rely primarily on rotational motion including the amusement apparatus of U.S. Pat. No. 5,060,932, the video simulation apparatus of U.S. Pat. No. 4,856,771 and the simulation device of U.S. Pat. No. 4,710,129. All of the above are geared towards simulating simultaneous roll, yaw and pitch or combinations thereof. Some of the above are also configured to be used with projected images for viewing by occupants as part of the simulation. The amusement ride of U.S. Pat. No. 4,066,256 is characterized by three substantially vertical hinged actuators which are moved in a controlled manner to displace a suspended horizontal platform, thereby simulating acceleration in the plane of the platform.
With known simulators the movement imparted by the motion base has been correlated with the presentation of visual images without regard to the physiological effect on passengers of that combination of image and motion. An unanticipated and unwanted consequence has been the frequent inducement of motion sickness. It has been recognized that motion sickness stems primarily from an improper relationship between visual images and the corresponding motion of a person's reference frame.
Simulators deceive the mind through the use of a combination of visual images coupled with limited motion of the passengers. To be effective, simulators must rely on tricking the inner ear with initial movement of the motion base synchronized with the "onset queues" presented as part of the visual image. The inner ear is sensitive to acceleration, i.e., the rate of change of velocity per unit time. The magnitude of acceleration is greatest at the onset of motion or at the onset of a change in motion. Consequently, it is most important for there to be strict correlation between the onset of the movement of the motion base and the corresponding visual image.
Angular motion of the frame of reference has been specifically demonstrated to be of great importance in causing motion sickness. For example, the driver of a car is least susceptible to motion sickness as compared to its passengers. Driver visual input is almost exclusively the view down the road towards the horizon. As such, the driver's frame of reference undergoes only orthogonal, rectilinear movement. In contrast, the passenger's frame of reference includes the other passengers as well as the vehicle's interior. The heaving and bobbing of that frame while driving is characterized by angular motion (e.g., roll, pitch and yaw).
Simulators, therefore, should correlate the physical and visual onset queues and avoid angular movement of that which comprises the passengers frame of reference, such as the vehicle interior. However, in the prior art there has been no recognition of the need to maintain orthogonal fidelity between motion and the visual images associated therewith or correlate onset queues. No prior art motion base is configured to constrain motion only in three orthogonal directions. In contrast, the prior art is unanimous in extolling the virtues of maximizing the degrees of freedom of the motion base and provide for rotational or angular motion of the vehicle, (roll, pitch and yaw) as they are directed at or derived from flight simulation and are constructed without regard the relationship between onset queues.
Known motion bases must be adapted to emulate orthogonal motion, requiring additional complexity in the controller. The hardware needed to simulate rotational motion is superfluous if only three orthogonal degrees of freedom are mandated. Moreover, the cost of these prior art motion bases are correspondingly excessive when movement is so limited. It would be desirable to have a simulator system which generates a more realistic simulation of an event in a simple and cost efficient manner while avoiding movement that has the potential for inducing motion sickness. The present invention is drawn towards such a simulator system.